342 LEGUMINOS^ PRODUCING TANNING MATTERS AND DYES 



Considerable use is made of this colouring matter in dyeing. The 

 chief export countries are Haiti, the English possessions in America, 

 Mexico, the Argentine, Guatemala, Martinique, Gaudeloupe, &c. 



The wood is cut into logs and shipped to Europe. 



Peltophorum Linnsi (Tree).— A Brazilian tree, the wood of which 

 contains an orange-coloured dye-stuff. The wood is known in com- 

 merce as Brasilette. 



Saraca indica (Tree). — The bark is used in medicine and appears 

 to be simply astringent. A sample from Bombay contained S'l of 

 tannin which, dn association with salts of iron, gave a greenish- 

 coloured dye-stuff. 



Vouapa Simira (Tree). — A dye-stuff is extracted from this plant in 

 Guiana. 



MIMOSE/E. 



Acacia arabica (Tree). — The bark is very astringent, and is one 

 of the most commonly used tanning substances in India. Dr. Leather 

 has obtained i6'4 per cent, of tannin, and Mr. Hooper i6'7 per cent., 

 from two samples from different localities. 



The husks give from 5 to 20 per cent, of tannin, according to their 

 state of maturity; the content is highest in the younger pods. 



Their composition is as follows : — 



Bark Pods 



)00"0 lOQ-O 



The pods are reduced to jiowder while still green, and in combina- 

 tion with salts of iron are used in the manufacture of ink. 



As regards tanning, experiments have shown these extracts to be 

 too deeply coloured for the European market, and their proportions 

 of soluble non-tanning substances are also too high, being fi'om 24*4 to 

 34' I per cent., while those vii commercial extracts range from 2*4 to 

 1 3' 7 per cent. 



The pods of this acacia yield the Indian bablaJi , which is used for 

 dyeing. These joods are blackish-grey in colour and covered with a 

 slight, whitish, extremely adherent down. 



Acacia concinna (Tree). — The bark of this acacia is used in the 

 south of India for tanning and dyeing. 



Acacia pycnantha (Tree). — An Australian variety the bark of which 

 contains 33 "8 per cent, of tannin. According to the Trnpical .Iffricul- 

 turistj the proportion may be as high as 40*2 and 49" 5 per cent. ; non- 

 tannins Q*o to Q'4 per cent. ; insoluble matter 20'6 to 3Q'6 per cent. 

 The bark is called golden wattle^ and is largely used in tanning. 



Acacia dealbata (Tree). — We make the average content of tannin 

 to be 13 to 14 per cent, with extremes of i2'2 to i/'S per cent. ; non- 

 tannins 4"3 per cent. ; insoluble matter 71 "g per cent. {Silver 7C'attle.) 



